Germ Cell Apoptosis and DNA Damage Responses

Abstract In the past 12 years, since the fi rst description of C. elegans germ cell apoptosis, this area of research rapidly expanded. It became evident that multiple genetic pathways lead to the apoptotic demise of germ cells. We are only beginning to understand how these pathways that all require the CED-9/Bcl-2, Apaf-1/CED-4 and CED-3 caspase core apoptosis components are regulated. Physiological apop-tosis, which likely accounts for the elimination of more than 50 % of all germ cells, even in unperturbed conditions, is likely to be required to maintain tissue homeo-stasis. The best-studied pathways lead to DNA damage-induced germ cell apopto-sis in response to a variety of genotoxic stimuli. This apoptosis appears to be regulated similar to DNA damage-induced apoptosis in the mouse germ line and converges on p53 family transcription factors. DNA damage response pathways not only lead to apoptosis induction, but also directly affect DNA repair, and a transient cell cycle arrest of mitotic germ cells. Finally, distinct pathways activate germ cell apoptosis in response to defects in meiotic recombination and meiotic chromosome pairing